Cheating
tag preemptively added. It doesn't matter if the story doesn't treat the cheating element seriously or use cheating as a theme. Some readers actively wish to avoid such content, so it's being tagged for their sake.
Bisexual
will not be added for now. This is not for lack of evidence, really. The older character is clearly married to a man and interested in someone of the same sex. However, we do not tag incidental bisexuality for (essentially) meaningless or off-screen characters. If the husband becomes more prominent, or bisexuality is explored as a theme, we'll re-visit it at that time.
If you wish to discuss tags further, please hop over to the Help thread. Cheers.